The present invention relates to an electrical junction box of a type that an electronic unit is contained therein, and also relates to a method of manufacturing such an electrical junction box.
In recent years, use of the electrical junction box has become diversified, and there are some electrical junction boxes which are provided with controlling function in addition to simple power distributing function. FIG. 10 shows an example of such an electrical junction box.
This electrical junction box 61 includes: a plurality of wiring boards 64 on which a number of electric wires 62 are arranged; terminals 63 for connectors to be electrically connected at appropriate positions of the arranged electric wires 62 are provided uprightly; an electronic unit 66 which is an electronic board carrying thereon electronic components 65; an upper casing 67 and a lower casing 68 which are made of electrically insulating material and adapted to contain these members.
On an outer face of the upper casing 67, there are formed connector housings (hood members) 69a, and the terminals on the wiring boards 64 are projected into the connector housings 69a, thereby to constitute connectors 69.
In this electrical junction box 61, a desired pattern of diverged circuits can be formed by the electric wires 62 on the wiring boards 64, and at the same time, wiring works inside the upper and lower casings 67, 68 can be mitigated by utilizing the terminals 63 which are directly provided uprightly on the wiring boards 64.
However, in this electrical junction box 61, since the terminals 63 of the connectors 69 are directly provided on the wiring boards 64, the connectors 69 are unable to be mounted on an area in which the wiring board 64 is not provided (an area in which the electronic unit 66 is provided). Thus, the connectors 69 are unable to be provided in a space S of the upper casing 67 which corresponds to an upper face of the electronic unit 66. Since the positions of the connectors 69 are thus restricted, the electrical junction box 61 has become inevitably large-sized, because provision of the connectors 69 must be ensured at other positions.
In this connection, there is such an idea that a through hole may be formed in an insulating board of the electronic unit 66, and the terminals 63 are passed through this through hole to install the connectors 69 in a space on the upper face of the electronic unit 66. However, this idea is not practical, because there are such inconveniences that formation of the through hole may lead to a rise of cost, and mounting positions of the electronic components 65 may be limited.
Besides the above described electrical junction box, there is another type of related-art electric junction box (not shown) to be mounted on an automobile or the like, which comprises: an upper casing and a lower casing made of synthetic resin; a plurality of bus-bar wiring boards arranged inside the lower casing; a plurality of housings which are integrally provided on the upper casing; terminals continued to the bus-bars made of electrically conductive metal and positioned inside the housings; and an electronic unit which is additionally provided, for example, on an outer face of the lower casing.
Electrical components such as connectors of exterior wire harnesses, relays, fuses and so on are connected to the housings, and electrical currents which have been inputted via the connectors from, for example, a power line of a vehicle are outputted from other connectors via the fuses and relays to loads such as external electrical equipments and auxiliaries. At the same time, signal currents are inputted into the electronic unit to control the auxiliaries such as an engine, an automatic transmission, etc.
In this electrical junction box, because the electronic unit has to be joined to the casing (a junction box body), the structure may become bulky and assembling performance may be bad. Further, because the electronic unit is arranged on the outer face of the lower casing, connections between the connectors and the fuses can be conducted only on the upper casing. Therefore, very few connections can only be conducted, and an increase of the electrical equipments and auxiliaries in the vehicle cannot be coped with.